Difference between import numpy and import numpy as np

Question

I understand that when possible one should use

import numpy as np

This helps keep away any conflict due to namespaces. But I have noticed that

Answer 1

numpy is the top package name, and doing import numpy doesn't import submodule numpy.f2py.

When you do import numpy it creats a link that points to numpy, but numpy is not further linked to f2py. The link is established when you do import numpy.f2py

In your above code:

import numpy as np # np is an alias pointing to numpy, but at this point numpy is not linked to numpy.f2py
import numpy.f2py as myf2py # this command makes numpy link to numpy.f2py. myf2py is another alias pointing to numpy.f2py as well

Here is the difference between import numpy.f2py and import numpy.f2py as myf2py:

• import numpy.f2py
  • put numpy into local symbol table(pointing to numpy), and numpy is linked to numpy.f2py
  • both numpy and numpy.f2py are accessible
• import numpy.f2py as myf2py
  • put my2py into local symbol table(pointing to numpy.f2py)
  • Its parent numpy is not added into local symbol table. Therefore you can not access numpy directly